Various forms of supports for mounting trays, or the like, on chairs are shown in prior patents. For example, in U.S. Pat. No. 3,166,354, a folding lawn chair in the form of a chaise lounge has a tray support clamped to an arm. The primary purpose of this patent is to level the tray. U.S. Pat. No. 2,503,543, shows an overstuffed chair having a pair of folding table top parts which may be swung in front of a person sitting in the chair to provide a continuous table top across the person's lap. In U.S. Pat. No. 2,710,051, a writing surface is clamped to the seat of a chair and may be adjusted up and down and to a limited extent may be moved to and fro across the front of the person as well as pivoted in a horizontal plane. However, when clamped to the chair this support does not permit free movement of the writing surface from front to rear along the side of the person. U.S. Pat. No. 1,284,596, shows a chair having a pair of mirrors mounted on slides pivoted to opposite arms of the chair and permitting movement of the mirrors toward and away from a person sitting in the chair as well as pivotal movement of the mirrors about a vertical axis. In U.S. Pat. No. 158,844, an ironing board has a slide received in a track mounted on a table so that the ironing board may be moved longitudinally of the table as well as swung about a generally vertical axis.